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Terahertz magneto-optical isolator based on graphene-silicon waveguide

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Science China(Information Sciences) 2022年第6期65卷 275-276页

作者： Dan ZHAO Fei FAN Tengfei LI Zhiyu TAN jierong cheng Shengjiang CHANG Institute of Modern Optics Nankai University Tianjin Key Laboratory of Micro-scale Optical Information Science and Technology College of Electronic Information and Optical Engineering Nankai University Tianjin Key Laboratory of Optoelectronic Sensor and Sensing Network Technology College of Electronic Information and Optical Engineering Nankai University

Dear editor,Optical isolators and circulators are non-reciprocal one-way transmission devices, which only allow light to transmit in one direction and prevent light from transmitting in the opposite direction. Thus, they can protect the light source and detector in the integrated microwave or optical system, and also significantly reduce the additional noises. However, due to the limitation of material and device mechanism,

关键词： graphene magneto-optical device isolator Waveguide Terahertz

Control of angular dispersion in dielectric gratings for multifunctional wavefront shaping and dynamic polarization conversion

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Photonics Research 2021年第11期9卷 2190-2195页

作者： YIWU YUAN jierong cheng FEI FAN XIANGHUI WANG SHENGJIANG CHANG Institute of Modern Optics Nankai UniversityTianjin 300350China Tianjin Key Laboratory of Micro-scale Optical Information Science and Technology Tianjin 300350China Tianjin Key Laboratory of Optoelectronic Sensor and Sensing Network Technology Tianjin 300350China

Compared with traditional optical elements,metasurfaces have shown unique advantages in multifunctionality encoded in different frequencies,polarization states,and orbital angular ***,the study of metasurfaces with well-controlled functions under different incident angles is still in its *** we propose a general method to tailor the angular dispersion over the simplest binary dielectric grating in the transmission *** demonstrate that the angular response is strongly related to the number of waveguide modes inside the grating,so one can intentionally reduce or enhance the angular dispersion by controlling the number of waveguide *** phase manipulation over incident angles is experimentally demonstrated by a metalens with angle-dependent *** angular dispersion in orthogonal polarization states is further utilized to demonstrate angle-insensitive and angle-multiplexed wave *** devices with simple configuration and clear physics offer a general platform to expand the scope of beam manipulation over metasurfaces.

关键词： polarization waveguide dispersion

Arbitrary large-gradient wavefront shaping: from local phase modulation to nonlocaldiffraction engineering

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Photonics Research 2022年第4期10卷 896-904页

作者： Xipu Dong jierong cheng Yiwu Yuan Zhenyu Xing Fei Fan Xianghui Wang Shengjiang Chang Institute of Modern Optics Nankai UniversityTianjin 300350China Tianjin Key Laboratory of Micro-scale Optical Information Science and Technology Tianjin 300350China Tianjin Key Laboratory of Optoelectronic Sensor and Sensing Network Technology Tianjin 300350China

The powerful wavefront manipulation capability of metasurfaces originates from their subwavelength or deep subwavelength elements with designable optical responses, especially phase responses. However, they usually suffer from performance degradation as the spatial phase gradient is large. To solve this issue, we propose an accurate and efficient nonlocal diffraction engineering mechanism to tailor an arbitrary large-gradient wavefront utilizing superwavelength-scale elements. The fast-varying phase profile is cut into segments according to 2π zones rather than subwavelength discretization. Each phase segment is accurately implemented by precisely tailoring the diffraction pattern of the element, where diffraction angles, efficiencies, and phases are controlled simultaneously. As proof of the concept, high numerical aperture cylindrical metalenses are designed using this method and experimentally validated at the terahertz band. The cylindrical metalens is further extended to a fullspace metalens, which enables high-quality subwavelength imaging with resolved details of 0.65λ. The proposed mechanism offers an efficient way to capture the fast-varying wavefront using relatively coarse geometries with new physical insights.

关键词： phase gradient local

Arbitrary terahertz chirality construction and flexible manipulation enabled by anisotropic liquid crystal coupled chiral metasurfaces

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Photonics Research 2023年第11期11卷 1880-1891页

作者： XINHAO JIANG YUNYUN JI FEI FAN SONGLIN JIANG ZHIYU TAN HUIJUN ZHAO jierong cheng SHENGJIANG CHANG Institute of Modern Optics Nankai UniversityTianjin 300350China Tianjin Key Laboratory of Micro-scale Optical Information Science and Technology Tianjin 300350China Tianjin Key Laboratory of Optoelectronic Sensor and Sensing Network Technology Tianjin 300350China

Chiral metasurfaces integrated with active materials can dynamically control the chirality of electromagnetic waves,making them highly significant in physics,chemistry,and ***,we theoretically proposed a general and feasible design scheme to develop a chiral metadevice based on a bilayer anisotropic metasurface and a monolayer liquid crystal(LC),which can construct and flexibly manipulate arbitrary terahertz(THz)*** the twist angle between the anisotropic axes of two metasurfacesθis not 0°,the spatial mirror symmetry of the chiral metadevice is broken,resulting in a strong THz chiral *** addition,the introduction of anisotropic LCs not only enhances the chiral response of the metadevice but also induces the flipping modulation and frequency tunability of the *** importantly,by optimizing theθ,we can flexibly design the arbitrary chiral response and the operating frequency of chirality,thereby promoting the emergence of various chiral manipulation *** experimental results show that the maximum circular dichroism can reach-33 d B at 0.94 THz and flip to 28 d B at 0.69 THz by rotating the LC optical axis from the x to y axis,with the maximum operating frequency tunable range of~120 *** expect this design strategy can create new possibilities for the advancement of active THz chiral devices and their applications,including chiral spectroscopy,molecular recognition,biosensing,and fingerprint detection.

关键词： chiral anisotropic crystal

基于神经网络的高角色散宽带介质超光栅的快速优化

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光学学报 2020年第23期40卷 9-16页

作者：李润泽董希谱程洁嵘常胜江南开大学现代光学研究所天津300350 天津市微尺度光学信息技术科学重点实验室天津300350 天津市光电传感器与传感网络技术重点实验室天津300350

由于超材料和超表面的亚波长结构单元的形状和尺寸具有很大的设计自由度,可对电磁波的振幅、相位、波前和方向等进行复杂而精确的调控,同时随着结构参数数量的增加,结构设计的时间往往呈指数增长。提出了一种基于反向传播(BP)神经网络... 详细信息

由于超材料和超表面的亚波长结构单元的形状和尺寸具有很大的设计自由度,可对电磁波的振幅、相位、波前和方向等进行复杂而精确的调控,同时随着结构参数数量的增加,结构设计的时间往往呈指数增长。提出了一种基于反向传播(BP)神经网络快速优化超表面结构的方法,实现了兼具高衍射效率、宽带宽和高角色散等优势的太赫兹介质超光栅。利用有限次数的严格耦合波分析建立的数据集来训练BP神经网络,可准确预测任意结构参数的超光栅衍射光谱,并通过遍历所有结构参数快速筛选出具有最高衍射效率且宽带宽的超光栅,相比传统的遍历计算方法速度提高了一万倍,证明了基于BP神经网络的超表面优化方法的高效性以及精准性,同时为太赫兹波段提供了一种性能优异的衍射元件。

关键词：光栅深度学习 BP神经网络超光栅优化

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裁判文书买卖合同法律性质之法理分析

北京航空航天大学学报（社会科学版） 2014年第2期27卷 34-41页

作者：陈界融四川大学法学院四川成都610064

终审裁判文书买卖合同,有违既判力主观范围效力原理,欲使终审裁判文书既判力主观范围以外的主体成为执行程序中的适格当事人,并且其以自己的名义向法院申请强制执行,这种漫无边际扩张既判力主观范围的企图,为法不许。裁判文书买卖合同... 详细信息

终审裁判文书买卖合同,有违既判力主观范围效力原理,欲使终审裁判文书既判力主观范围以外的主体成为执行程序中的适格当事人,并且其以自己的名义向法院申请强制执行,这种漫无边际扩张既判力主观范围的企图,为法不许。裁判文书买卖合同与诉讼担当、诉讼信托皆有本质区别,既不能将之归入任意的诉讼担当制度,也不能归入诉讼信托范畴,且诉讼信托,亦为法所不许。裁判文书买卖合同对象之强制执行请求权,它不具有金融资产本身所应具有的很强的流通性、人为的可分性、名义价值不变性等特性,不属于金融资产转让合同。债权凭证转让合同的标的,一改裁判文书买卖合同标的之人身性、公法性而具有流动性、财产性,属于合法的资产交易对象,债权凭证转让合同应当合法、有效。

关键词：裁判文书买卖诉讼信托诉讼担当保理债权凭证

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基于几何相位的亚太赫兹波宽带平面透镜

中国科学：物理学、力学、天文学 2021年第5期51卷 49-55页

作者：程洁嵘董希谱王娇范飞王湘晖常胜江南开大学现代光学研究所天津300350 天津市微尺度光学信息技术科学重点实验室天津300350 天津市光电传感与传感网络重点实验室天津300350

几何相位,又被称为Pancharatnam-Berry相位,因设计简单、相位延迟可覆盖2π范围且与频率无关等优势在光学超表面中被广泛用于波前操控.几何相位超表面的效率和带宽往往受限于其结构单元实现正交偏振变换的能力.当工作频率偏离设计频率时... 详细信息

几何相位,又被称为Pancharatnam-Berry相位,因设计简单、相位延迟可覆盖2π范围且与频率无关等优势在光学超表面中被广泛用于波前操控.几何相位超表面的效率和带宽往往受限于其结构单元实现正交偏振变换的能力.当工作频率偏离设计频率时,结构单元往往不能完全改变入射圆偏振光的手性,导致仅被改变手性的部分光波波前被调控,而其余光波未被调控.为此,本工作提出了一种几何相位超表面透镜,得益于其结构单元的高效率、宽频带的正交偏振变换能力,该透镜可实现亚太赫兹波束的宽带聚焦.其结构单元为一维低折射率介质光栅,可在130-165 GHz的范围内实现正交偏振变换.通过旋转、截断和拼接此光栅构成二维平面透镜,数值仿真表明该透镜在60-160 GHz的宽带范围内,均保持在40%以上的聚焦效率.超表面透镜的带宽远大于其结构单元的偏振变换带宽,这是由光栅不同的截断长度导致的.这款透镜可以采用3D打印进行加工,制作方便,成本低廉,对发展紧凑型亚太赫兹波束操控元件具有重要意义.

关键词：几何相位太赫兹光栅透镜宽带

Inverse design on terahertz multilevel diffractive lens based on 3D printing[Invited]

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Chinese Optics Letters 2023年第11期21卷 45-50页

作者：石晨雨王宇刘琼峻陈赛赵蔚鹏吴晓君程洁嵘常胜江 School of Electronic Information Engineering Beihang UniversityBeijing 100191China Institute of Modern Optics Nankai UniversityTianjin 300350China

Terahertz(THz)lenses have numerous applications in imaging and communication ***,the common THz lenses are still based on the traditional design of a circular convex *** this work,we present a method for the design of a 3D-printed multilevel THz lens,taking advantage of the benefits offered by 3D printing technology,including compact size,lightweight construction,and *** approach utilizes an inverse design methodology,employing optimization methods to promise accurate *** reduce simulation time,we employ the finite-difference time-domain method in cylindrical coordinates for near-field computation and couple it with the Rayleigh-Sommerfeld diffraction theory to address far-field *** technology holds great potential for various applications in the field of THz imaging,sensing,and communications,offering a novel approach to the design and development of functional devices operating in the THz frequency range.

关键词： THz lens 3D printing achromatic lens THz communication

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太赫兹液晶可调谐功能器件

中国激光 2019年第6期46卷 50-63页

作者：冀允允范飞于建平许士通程洁嵘王湘晖常胜江南开大学现代光学研究所天津300350 天津光电子传感器与传感网络技术重点实验室天津300350 中国科学院长春光学精密机械与物理研究所应用光学国家重点实验室吉林长春130033

介绍了不同液晶材料在太赫兹(THz)波段的光学各向异性和外场调制特性。在此基础上,综述了几种基于液晶与人工电磁微结构相结合的THz功能器件,该器件可实现对THz波的调谐滤波、电磁诱导透明、相位调制以及偏振控制功能等;系统地分析了液... 详细信息

介绍了不同液晶材料在太赫兹(THz)波段的光学各向异性和外场调制特性。在此基础上,综述了几种基于液晶与人工电磁微结构相结合的THz功能器件,该器件可实现对THz波的调谐滤波、电磁诱导透明、相位调制以及偏振控制功能等;系统地分析了液晶与人工电磁微结构的相互作用机理、THz波长尺度下液晶的外场调控规律与表面相互作用。此外,还对THz液晶光子器件的研究发展趋势进行了展望。

关键词：太赫兹技术石墨烯光子晶体超材料液晶器件